The present invention generally relates to controlled fragmentation warheads and more particularly to an improved method for producing a controlled fragmentation warhead case. Specifically, the present invention provides a method of manufacturing a controlled fragmentation grid on the interior surface of a cylindrical casing used for a warhead or other ordnance device.
Existing methods for incorporating controlled fragmentation in warheads and other ordnance devices typically involve costly and lengthy processes. Alternative methods of producing controlled fragmentation warheads have been thoroughly investigated but have failed to develop a method which significantly reduces the time, cost, and simplifies the processing required to produce controlled fragmentation warheads.
A widely used method of producing controlled fragmentation warheads involves machining grooves on the interior surface of the casing. Machining individual casings, however, represents an additional step in the manufacturing process and thus represents a time consuming and relatively expensive method of incorporating controlled fragmentation.
Another particularly unique method of producing controlled fragmentation warheads is disclosed in U.S. Pat. No. 2,933,799. Such method involved forming spaced notches in a stock bar by a punch-pressing operation, winding the notched bar in a helix, and then welding adjacent turns of the helix with a continuous weld. The welded helix may then be cut in any desired lengths to form warheads of any desirable size.
Still another conventional method of fabricating controlled fragmentation warheads is by the process of casting the warheads in a casting form having a grooved pattern. Due to the time intervals involved in the casting operations, this method is impractical for mass production purposes since it requires numerous casting forms in order to compensate for the time loss in each casting form and a prohibitively large manufacturing plant to install the numerous casting forms required. Moreover, experience has shown that cast-produced warheads are unsatisfactory due to erratic fragmentation and due to pulverization into useless chaff of a substantial portion of the warhead.
Notwithstanding these related methods, there still exists a need to develop a lower cost method of producing controlled fragmentation warheads.